Mechanism-Based Inactivation of Human Cytochrome P450 3A4 by Two Piperazine-Containing Compounds
作者:Amanda K. Bolles、Rina Fujiwara、Erran D. Briggs、Amin A. Nomeir、Laura Lowe Furge
DOI:10.1124/dmd.114.060459
日期:2014.12
Human cytochrome P450 3A4 (CYP3A4) is responsible for the metabolism of more than half of pharmaceutic drugs, and inactivation of CYP3A4 can lead to adverse drug-drug interactions. The substituted imidazole compounds 5-fluoro-2-[4-[(2-phenyl-1 H -imidazol-5-yl)methyl]-1-piperazinyl]pyrimidine (SCH 66712) and 1-[(2-ethyl-4-methyl-1 H -imidazol-5-yl)methyl]-4-[4-(trifluoromethyl)-2-pyridinyl]piperazine (EMTPP) have been previously identified as mechanism-based inactivators (MBI) of CYP2D6. The present study shows that both SCH 66712 and EMTPP are also MBIs of CYP3A4. Inhibition of CYP3A4 by SCH 66712 and EMTPP was determined to be concentration, time, and NADPH dependent. In addition, inactivation of CYP3A4 by SCH 66712 was shown to be unaffected by the presence of electrophile scavengers. SCH 66712 displays type I binding to CYP3A4 with a spectral binding constant ( K s) of 42.9 ± 2.9 µ M. The partition ratios for SCH 66712 and EMTPP were 11 and 94, respectively. Whole protein mass spectrum analysis revealed 1:1 binding stoichiometry of SCH 66712 and EMTPP to CYP3A4 and a mass increase consistent with adduction by the inactivators without addition of oxygen. Heme adduction was not apparent. Multiple mono-oxygenation products with each inactivator were observed; no other products were apparent. These are the first MBIs to be shown to be potent inactivators of both CYP2D6 and CYP3A4.
人细胞色素P450 3A4(CYP3A4)负责代谢超过一半的药物,CYP3A4的失活可能导致不良的药物-药物相互作用。先前已鉴定出取代咪唑化合物5-氟-2-[4-[(2-苯基-1H-咪唑-5-基)甲基]-1-哌嗪基]嘧啶(SCH 66712)和1-[(2-乙基-4-甲基-1H-咪唑-5-基)甲基]-4-[4-(三氟甲基)-2-吡啶基]哌嗪(EMTPP)为CYP2D6的基于机制的失活剂(MBI)。本研究显示,SCH 66712和EMTPP同样是CYP3A4的MBI。SCH 66712和EMTPP对CYP3A4的抑制作用被确定为浓度、时间和NADPH依赖性的。此外,SCH 66712对CYP3A4的失活作用在存在亲电子清除剂的情况下不受影响。SCH 66712显示出I型结合到CYP3A4,光谱结合常数(Ks)为42.9 ± 2.9 µM。SCH 66712和EMTPP的分区比分别为11和94。全蛋白质质谱分析揭示了SCH 66712和EMTPP与CYP3A4的1:1结合化学计量比,以及与失活剂结合的质量增加,且没有氧的添加。血红素加合物不明显。观察到每个失活剂的多个单氧化产物;没有其他产物明显。这些是首次被证明对CYP2D6和CYP3A4都有强失活作用的MBI。